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是不是这个？ Parasitic and predatory arthropods often prevent plants from being severely damaged by killing herbivores as they feed on the plants. Recent studies show that a variety of plants, when injured by herbivores, emit chemical signals that guide natural enemies to the herbivores. It is unlikely that herbivore-damaged plants initiate the production of chemicals solely to attract parasitoids and predators. The signaling role probably evolved secondarily from plant responses that produce toxins and deterrents against herbivores and antibiotics against pathogens. To effectively function as signals for natural enemies, the emitted volatiles should be clearly distinguishable from background odors, specific for prey or host species that feed on the plant, and emitted at times when the natural enemies forage. Our studies on the phenomena of herbivore-induced emissions of volatiles in corn and cotton plants and studies conducted by others indicate that (i) the clarity of the volatile signals is high, as they are unique for herbivore damage, produced in relatively large amounts, and easily distinguishable from background odors; (ii) specificity is limited when different herbivores feed on the same plant species but high as far as odors emitted by different plant species and genotypes are concerned; (iii) the signals are timed so that they are mainly released during the daytime, when natural enemies tend to forage, and they wane slowly after herbivory stops. 下面是中文翻译。 寄生虫和食肉的节肢动物通常用杀死食草动物的方式来保护植物不被严重伤害。最近的研究表明，很多植物，当被食草动物伤害的时候，会发射出化学信号引来这个食草动物的天敌。被食草动物损坏的植物不太可能产生只吸引寄生虫和食肉动物的化学东西。这个信号作用可能还包括从植物的反映产生毒素和制止物来防止病原体。为了有效地吸引食草动物的天敌，散发出来的变化无常的东西应该和背景气味有很大区别，尤其是对那些食草或者寄生在草上的动物来说。而且这个化学东西间断的发射当有天敌攻击时。我们从玉米和棉花职务上研究了食草动物导致变化无常物质散发的现象，和其他发面得出的结论：1. 不明气体的清晰度很高，因为他们对于食草动物的伤害是独特的，大量产生而且容易辨别。2.特殊性被限制了，当不同的食草动物在同一个植物上获取食物，但是会变得多只要考虑不同植物发出的气味和基因型。
3.信号是同步的，所以他们主要在白天发射，也就是天敌出来找食物的时候，而且在食草行为停止时气味散发也满满停止。
[此贴子已经被作者于2009-3-3 20:33:52编辑过] | 
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发表于 2009-3-3 20:13:00
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